The cattail genus (Typha spp.) is an erect, perennial freshwater aquatic herb which can grow 3 or more meters in height. The linear cattail leaves are thick, ribbon-like structures which have a spongy cross-section exhibiting air channels. The subterranean stem arises from thick creeping rhizomes. North American cattails have minute, brown colored male flowers (staminate) thickly clustered on a club-like spadix. The lower portion of the spadix bares the female flowers (pistillate). There are three species and several hybrids in the cattail genus which occur in North America.[1][2][3]Typha latifolia, broad-leaved cattail, is distinguished from T. angustifolia, narrow-leaved cattail, by the relative width of the leaf and the position of the staminate and pistillate portions of the spadix (heads).

Typha latifolia has 6-23 mm wide leaves that are flat, sheathing, and pale grayish-green in color. Typha angustifolia has 3-8 mm wide leaves that are full green and somewhat convex on back.[4] In T. latifolia the staminate and pistillate heads are contiguous or nearly so, whereas in T. angustifolia the heads are separated by approximately 3 cm. Cattail fruits differ among the two major species. Typha angustifolia fruits are about 5-8 mm long with hairs arising above the middle. Typha latifolia fruits are about 1 cm long with hairs arising near the base.[4] The tall cattail (Typha domingensis) may be difficult to separate from T. angustifolia. Typha domingensis is usually taller and has flattened and more numerous leaves.[5] Hybrids of intermediate appearance have been reported, and are often referred to as the species Typha x glauca.

Stewardship summary

Cattail control is an important consideration for natural areas. Monitoring the spread of cattails by aerial surveys and sampling transects can help determine the extent of cattail monocultures. Research into new biological control methods and the recovery of communities after cattail management needs to be conducted. Control techniques of fire and physical removal (cutting) in conjunction with flooding are most appropriate.

Cattail management may be desired in situations where cattails have responded to wetland disturbance by growing in dense monocultures. The genus Typha can behave like aggressive introduced weeds in a variety of natural communities throughout North America.[5] Cattails are considered serious weeds in some countries [6][7] but not necessarily in North America. In high-quality natural communities, cattails usually occur as scattered sterile plants.[5] With disruptions to a community, cattail populations may respond by spreading vegetatively at a rapid rate. The effect of the growth spurt is closing open water, eliminating habitat and species diversity, and reducing the opportunity for other plants to become established and survive. Shading is a significant effect on other plants. Cattails are successful because they form extensive monocultures very rapidly through vegetative reproduction and maintain their dominance with the formation of dense rhizomes mats and litter.

Cattails have a wide ecological amplitude compared to other species.[8] They are tolerant to habitat changes, pollutants in the water system, and saline or basic substrates. A study in Indiana concluded that the three basic events precede the growth of cattails monocultures:

Claims that hybrid cattails are responsible for monoculture growths have not been confirmed.

Natural history

Range

Cattails have a cosmopolitan distribution and a wide ecological amplitude.

Typha latifolia is found throughout North America from sea level to 2134 M (7000 feet) elevation.

Typha angustifolia is widely distributed in the eastern and northern United States.

Typha domingensis has a range which extends from the southwest United States, southern California and east to southeastern Virginia.

Habitat

Typha can be found in wetlands, sedge meadows, along slow moving streams, river banks, and lake shores. The plant is found in areas of widely fluctuating water levels such as roadside ditches, reservoirs and other disturbed wet soil areas. Cattails commonly invade the pelagic zones of bogs.[10] Typical associates include Phragmites australis, Lythrum salicaria, Spartina sp., Acorus calamus, Scirpus sp., and Sagittaria latifolia. Typha augustifolia is generally restricted to unstable environments, often with basic, calcareous, or somewhat salty soils.[11] Narrow-leaved cattail can grow in deeper water compared to T. latifolia, although both species reach maximum growth at a water depth of 50 cm (20 inches).[12] A robust hybrid between narrow-leaved and broad-leaved cattail, Typha x glauca, has similar habitat requirements to T. angustifolia.

Typha latifolia is the only species of cattail usually found in relatively undisturbed habitats throughout North America.[3] The tolerance of T. latifolia to high concentrations of lead, zinc, copper, and nickel has been demonstrated.[13] This species has been employed in secondary waste water treatment schemes.[14]

Typha latifolia is found in the most favorable sites where it competes against other species. Typha angustifolia and T. domingensis are restricted to less favorable and more saline habitats when they occur with T. latifolia.[10]Typha latifolia often displaces T. angustifolia in shallow (<15 cm) water, restricting the latter species to deep water.[12]Typha angustifolia is considered a pioneer in secondary succession of disturbed bogs.[9] Presumably, an increase in the acidity of a bog would lower the pH and reduce the invasion of T. angustifolia. Theodore Cochran (pers. comm)[15], of the University of Wisconsin-Madison herbarium states that most early herbarium specimens are T. latifolia and only recently have T. angustifolia specimens been collected from Wisconsin wetlands.

Cattails can grow on a wide gradient of substrate types. Wet pure sand, peat, clay and loamy soils have been documented under cattail stands. World wide distribution of cattails is summarized by Morton (1975)[6].

Ecology

Cattails flower in late May and June and sometimes later (up to late July) depending, perhaps, on soil and water temperatures as influenced by climate and litter in a stand. The wind-borne pollen attaches to stigmas of female florets to eventually produce achene fruits. The elongated embryo and stalk are covered with fine, unmatted hairs that aid in wind dispersal. Fruits are mature in August and September. Seeds are very small, weighing 0.055 mg each.[16]

Many cattail germination studies have been conducted. Some of these suggest that germination requirements are few. Seed germination can be 100 percent in slightly flooded conditions.[3]Typha latifolia seeds are less tolerant to salt (NaCl) concentrations in the substrate when compared to T. angustifolia seeds. However, seeds of both species which had been soaked in salt solution would germinate after being returned to non-saline conditions.[17]Typha angustifolia seeds showed no significant germination response when sprouted along a moisture gradient which ranged from 5 cm below substrate to 10 cm above.[16] Other studies have confirmed that water is required at a depth of 2.54 cm for germination. Sifton (1959)[18] showed light and low oxygen tensions affected germination of broad-leaved cattail.

Van der Valk and Davis (1976)[19] suggested that the germination of Typha seeds could be inhibited by an allelopathic interaction caused by Typha litter. Seed longevity and dormancy may be affected by soil moisture, temperature and soil atmosphere.[20][21][22][23]

Young Typha shoots grow rapidly from seeds in favorable substrates. Cattail colonies are commonly maintained by vegetative reproduction. A perennial root stock is the major organ responsible for reproduction.[5] Cattail productivity has been well documented. Net annual production has usually been estimated as the maximum standing crop (shoot biomass) values for a good site are generally between 1000 and 1700 g/m (d.w.).[10] Figures for Typha production mostly exceed the average standing crop yields for maize and sorghum.

Shoot density reports (numbers of stems per square meter) range from 28/m2[24] in Wisconsin to an extreme example reported by Dykyjova, et al. (1971)[25] of 108/m2. In a greenhouse experiment, ninety-eight vegetative shoots and 104 crown buds were produced on a single seedling during its first year.[26] Cattails can produce 20,000-700,000 fruits per inflorescence.[27][28][29] Vegetative growth by broad-leaved cattails of 518 cm (17 feet) annually have been recorded [30], and plants grown from seed flowered the second year.[27][3]

Cattail plants produce a dense rhizome mat and the clustered leaves produce a thick litter layer. Dense cattail growth and litter may reduce the opportunity for other plants to establish or survive.[31]

Calculations show that a natural stand of cattails may fix 18 kg nitrogen/ha/yr or approximately 8% of the total nitrogen present in the standing crop.[32]

The structure of cattail stands as it is, with upright leaves, high leaf area, balanced horizontal and vertical distribution of leaf area and shifts in leaf angle are all factors which permit monoculture success. An open, generously sunny habitat and abundant moisture can provide the setting for maximum cattail production.

Typha plants are mined by caterpillars of the moths Arzama opbliqua and Nonagria oblonga.[33] Aphids and Colandra pertinaux (the snout beetle) also feed on Typha leaves and stems. The stems may have many species of pupa living within them.[33] The cattail rhizomes provide food to mammals such as the muskrat. The grazing of muskrats may greatly influence cattail communities. A cycling population of muskrats may reach such a density so as to totally set back a cattail stand for the season. These "eat outs" are important to maintain open water in a balanced system. Muskrats utilize leaves and stems for houses and eat the rhizomes.[34] Cattail fruits provide nesting material for terrestrial birds and dry stems may be used by aquatic birds. Above ground portions die in the late fall and rhizomes overwinter. In Wisconsin, it was found that average winter marsh temperatures greater then 8°C reduced carbohydrate reserves in Typha latifolia to an extent sufficient to inhibit shoot growth in the spring.[35] Cattail population success has been correlated with nutrient fertility (Boyd 1971), water level and substrate temperature.[35]

The plant tissues can store relatively high concentrations of some metals. Typha appears to have an internal copper and nickel tolerance mechanism. It is not likely that there is an evolutionary selection for heavy metal tolerance, but rather it is inherent in the species.[13]

Management/Monitoring

Management Requirements

Cattails are often purposefully encouraged in some areas to stabilize shorelines from wave action erosion, or ice heaving. Two-thirds of wave energy will dissipate in two meters of cattail beds.[36] They have been used to reduce salinity in rice field[29] and have been considered "scrubbers" in polluted aquatic systems.[14] Commercial uses of cattails include footwear, roofing and floor mats. The species has been considered as an important source of protein [6] and a fuel source. The objective of management is not to eradicate cattails, but rather to control their spread in natural communities. Specifically, the goals of management should be to:

Control the spread and domination of potential habitat by cattail in and adjacent to natural areas.

Circumvent declines in other plant species with cattail proliferation.

Prevent development of monotypic cattail growth and loss of habitat heterogeneity.[37][38]

Management of cattails should be site specific and could include such active measures as hand cutting root stalks, burning and flooding, or shading.

Management Methods

Water level modification

High water conditions in a cattail stand can affect the growth of seedlings, can break off mature stalks, or can be followed by the immigration of muskrats which eat the cattail.[34] The effect of flooding does not always have negative impacts on cattails -- plants have been known to float up and continue growing until water returns to a previous lower levels.

As with any control measure, temporary conditions, such as flooding, do not prevent later seed establishment. Cattail seeds can arrive from a great distance, and it doesn't take but a few seeds to germinate and rapidly produce clones as adults. The cost of management actions should be considered when dealing with unknown response variables.

Low water conditions, maintained by draining a wetland, significantly effects the overall community.[39] Harris and Marshall (1963)[40] concluded that draining techniques have possible detrimental effects because the plant composition of a wetland can be radically changed. Draining alone can cause a significant increase in Typha cover under some conditions.[39] However, to inhibit Typha growth, a wetland can be drained and then burned during the summer. If there is no reserve of water over winter cattails will not survive the following spring, according to Zimmerman (pers. comm.)[34] but there have been no controlled experiments to show this.

Two years of 65 cm (26 in) deep flooding was required before established cattail began to die and open water conditions were created at Sinnissippi Marsh. Cattail initially survived flooding from 1973-1977 and became the dominant emergent plant. A light green color, noticeably narrower leaves, and absence of fruiting heads indicated stress in 1976. Cattail stem densities declined 57% with all emergent plants dead in 1977. Horicon Marsh, flooded to a depth of 40 cm (16 in), showed declines in emergent and aquatic plants. Cattail required two years before it declined.[41][42]

Mature T. latifolia and seedlings less than one year old are killed by water depths of 63.5 cm (25 in) and 45 cm (18 in) or more, respectively. Narrow-leaved cattail was unaffected by this degree of flooding. Narrow-leaved cattail establishment was prevented when water levels were maintained at 1.2 m (47 in) or deeper.[43] Dryer conditions allowed more clones of T. angustifolia to be spread.[17]

Because cattails can transpire significant quantities of water (2-3m of water/acre/year) [44][45], their establishment may serve to exacerbate water level instability and further contribute to disruptive influences supporting increased cattail. Flooding must account for evapotranspirational losses of water to maintain a level effective in cattail control.

Chemical Control

For designated preserves or natural areas, especially where system-orientated stewardship is used, chemical applications may not be appropriate. This is particularly true because cattail is an element of certain natural communities. However, use of chemicals to control an overabundance of cattail may have certain applications. Spraying Dalpan®[46] at 8.8-35.3 kg/acre (4-16 lb/acre) produced 74-97% reductions in cattails ten months after a mowed area was sprayed. Cattail regrowth was sprayed at 58-90 cm (24-36 in) height in September. Control was most effective when treated areas could be flooded to 10-15 cm (4-5 in) or deeper. Dalpan® spray achieved varied success but greatest control occurred where cattail stems were cut below water depths regardless of the herbicide quantity used. Poorest results were attained in areas with shallow fluctuating water levels. Spraying mature cattails rather than regrowth after cutting gave better results. Weller (1975)[47] had similar results with spraying where Amitrol®, Rodopan®, and Douupon® herbicides were effective in creating and maintaining openings for at least three years after spraying, but areas were quickly invaded by peripheral cattail. High doses of MCPA or 2,4-D in diesel oil (2.2-4.5 kg per acre) were effective if applied during flowering. Dalpan® (9 kg/acre) and Amino-triazole® (.91-1.36 kg/acre) gave good control results in Montana.[26] Herbicide applications were found necessary for up to three years in some areas. Similar results were found by Grigsby et al. (1955)[48], Heath and Lewis (1957)[49], Krolikowska (1976)[50], Pahuja et al. (1980)[51], Singh and Moolani (1973)[52], and Wisconsin Department of Natural Resources (1969)[41].

Wick and spray applications of Roundup® followed by manual clipping of all cattail stems was the treatment conducted by Applied Ecological Services and All Services Company (1985)[53] at a pond in northern Illinois. Cattail seeds were just at ripening stage at the time of treatment. Retreatment of Roundup® several weeks later and subsequent die-off proved this method successful.

Herbicide treatment at flowering may stress the cattail plants more than at other stages since the energy investment by the plant has been channeled into flowering.

Mechanical control

Hand or mechanical cutting of cattails followed by submergence of all cattail stems results in high control. Up to 100 percent cattail control was measured two growing seasons after treatment. No visible cattail regrowth occurred in one year and cattail rhizomes were dead. The highest cattail control of any method tested was achieved by two clippings followed by stem submergence to at least 7.5 cm (3 in).[46] Control was best if plants were cut in late summer or early fall.

In Iowa [47], cutting cattail and reflooding with at least 8 cm (3.1 in) of standing water over plant stems was effective. Weller (1975) [47]also found clipping cattails too early in the growing season (e.g. May) stimulated their growth and resulted in a 25 percent increase in stem counts the following year, with an eventual decline to preclip levels. August clipping controlled up to 80 percent of cattail only if followed by submergence. It was important to remove all dead and live cattail stems to achieve this control. Cutting shoots below the water surface two or three times in one growing season before flower production reduced a cattail stand by 95-99 percent in Montana and Utah.[54] Similar results were demonstrated by Shekhov (1974)[55] and Sale and Wetzel (1983)[56].

When shoots are cut below the water level, nearly all the oxygen is consumed in a short time, necessitating anaerobic respiration. In Typha, ethanol is produced accompanied by tissue breakdown after an oxygen shortage. Typha is ill adapted to deprivation of oxygen. Cuttings later than flowering stage are effective only in preventing regrowth for that year and may have no effect on subsequent years.[55]

Cattail control by injuring developing rhizomes and shoots was investigated.[47] Crushing and reflooding showed that cattails injured after June had poor recoveries. Success of crushing depended on the load used, number of times an area was crushed, and standing water depths after treatment. Spring and early summer treatments generally created favorable seedbeds for cattail and required a fall crushing to control seedlings. Crushing involved pulling a 55 gallon water filled drum behind a tractor. Deeper water areas showed highest control (up to 100 percent) while regrowth occurred in shallow areas. Although not practical for natural areas management, discing[47] and blasting [46] have also been investigated as methods of cattail control.

Prescribed burning

Fire alone was found to provide little or no cattail control.[46] Fires that destroyed cattail roots offered control; however, most fires only burned above-ground biomass and did little to control cattail. Drying in readiness for burning was effective cattail control when done for two years in arid Utah. Water was pumped from wetlands and then cattail stands were allowed to sun dry.

Water level drawdown, burning (Spring, Fall, and mid-growing season), and reflooding to 20-35 cm (8-18 in) water depth or deeper controlled cattail. Fire was found useful for cattail litter cleanup and assisted access for mowing or hand clipping.[47][46][39]

Shading

Black polyethylene tarps were used to cover cattails in an attempted control measure.[46] Actively growing cattail tips were killed when completely covered for at least sixty days. Greatest control was achieved in July when food resources of cattail were presumed to be lowest.[57] Problems with holding tarps down and their degradation confounded this investigation. Cattail is generally not shade tolerant.

Monitoring

Cattail control or reduction may be desirable where noticeable increases threaten natural plant diversity and habitat heterogeneity. Increases in the rate of spread and growth of a colony may signal management action. The establishment of cattails in non-wetland areas should be monitored. Gross area monitoring is necessary to determine the effects of management practices and the needs for future management.

Aerial surveys are used to document by photographs the spread of cattail colonies.[9] The advance of cattail clones can also be documented by placing permanent markers at the leading edge of colonies. Sampling along shore to water transects using 1 square meter quadrats allows an estimate of percent cover, stem density, and importance value of species. Shore to water transects with the line intercept methods show changes in density and spread.

Research

Research objectives in the past have concentrated on the effect of cattails on waterfowl production, sewage treatment, fuel production or recreational opportunities. There have been few studies on the methods of control of cattails in designated nature preserves or natural areas. More effort needs to be put into research with biological diversity and natural area maintenance as the major objectives.

Biological control has not been documented or researched. The effects of shading, day length, or varying light intensity on cattail reproduction is largely unknown.[5] There is no data to test the concerns that a fire used to control or destroy Typha rhizomes would destroy other plants or the wetland seed bank. Recent evidence (Apfelbaum unpub. data) suggests repeated annual spring burning in cattail dominated systems stimulates Cyperaceous seed germination even beneath a dense cattail canopy. Whether this is related to litter removal, actual fire scarification or other causes is unknown. More case studies and data related to the recovery of the natural community after cattail control, particularly fall burning, is an important need for future study. The interactions between animals, water level, and cattail growth need to be studied.[34] Cost effectiveness of the various methods available for cattail control is an important consideration.

↑ Mallik, A.U. and R.W. Wein. 1985. Miscroscale succession of bogged paludification of a Typha marsh. Presented at the Twenty-first Annual Meeting of the Canadian Botanical Association, University of Western Ontario, Long, Ontario. June 23-29, 1985.39.039.139.2

↑Singh, S.P. and M.K. Moolani. 1973. Changes in the chemical composition of cattail induced by herbicides. Proc. All India Weed Control Semin. 3:75.

↑Applied Ecological Services and All Services Company, 1985. Report on effects to control cattails (Typha angustifolia and T. latifolia) at the Swain family pond. Libertyville, Illinois. Unpublished report.